In the field of high speed printing, the belt or chain type of character carrier has a plurality of slugs with characters thereon and the slugs, along with their characters, are spaced as closely as possible. The principal motivation for using the horizontal or train type of character carrier is for improved print alignment, and along with such closely spaced characters, higher printing speeds are achieved. As is well known, the use of a type drum for high speed printing has the disadvantages of both higher cost and the occupation of more space, so the belt or chain type carrier is rapidly replacing the type drum in certain applications.
Various ways and means have been developed over the years in printers to increase the speed of printing while decreasing cost and size of such units. It is, of course, extremely important that the quality of the print, as to clearness and sharpness of the printed matter, be maintained so that smudging, ghosts, or the like do not exist. In the case of type drums, the hammer tip is sometimes curved in a manner to conform or coincide with the curvature of the drum and of sufficient magnitude to cover substantially more area than that of a single character, such as is disclosed in Hartley U.S. Pat. No. 2,776,618. Likewise, Rosen et al. U.S. Pat. No. 2,805,620 shows a hammer face curved generally in accordance with the drum surface. A type bar with interchangeable type having curved faces is disclosed in Redmond U.S. Pat. No. 2,862,592. Also, Wilkins et al. U.S. Pat. No. 3,090,297 shows a hammer slug with a curved face compatible with that of the type drum. A different approach in a curved hammer face is disclosed in Pensavecchia et al. U.S. Pat. No. 3,185,083 wherein the impact tip is curved away from the curvature of the drum. Solheim et al. U.S. Pat. No. 3,309,989 provides ribbon guides supported in a curved manner to clear adjacent characters upon hammer impact, and finally, Muterspaw U.S. Pat. No. 3,604,347 discloses a concave shaped face to provide uniform print density.